ADR-0027 Reduced-Field Synthesis: certs with no per-window array now get total
glazing = 0.148 x TFA x band-multiplier (median + quartile multipliers fit from
the 1000 real 21.0.1 certs), split 4-way across N/E/S/W with width=area/4,
height=1.0; glazing_type routed through the verified 21.0.1 cascade. Also guard
optional PhotovoltaicSupply.none_or_no_details (a parse straggler). Corpus maps
983/1000, up from 974.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Required->optional defaults (kw_only + data-driven from corpus presence) so
993/1000 certs that omit sap_windows parse, and honest Union[str, DescriptionV1]
typing for description/dwelling_type which the corpus lodges as localised dicts
in ~half the certs. The never-run 20.0.0 mapper path now produces EpcPropertyData;
974/1000 corpus certs map (xpass), up from 7.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Pulls in 42 commits of calculator/mapper accuracy fixes from the per-cert
mapper-validation and floor/roof/heating fronts.
Conflict resolutions:
- mapper `_is_elmhurst_roof_window`: main dropped the branch's "wall location →
vertical" guard (it broke cert 000516's rooflight), but that re-broke cert
001431's two External-wall U>3.0 windows (which must stay vertical). The two
certs lodge a BYTE-IDENTICAL §11 row, so neither location nor U separates
them — the real discriminator is the room-in-roof context. Replaced the
unconditional U>3.0 backstop with one gated on the BP having a room-in-roof
(`_elmhurst_bp_has_room_in_roof`): 000516's Main BP has a "Room in roof type
1" (→ rooflight), 001431's does not (→ vertical). Validated against BOTH —
full Elmhurst worksheet suite 1038 pass + the 001431 window-extraction pin.
- property_postgres_repository: kept main's `ids_by_uprn` method + the branch's
`_restrictions_of` helper.
- sap_fuel.py: the branch relocated it to domain/billing/ (already carrying
main's to_table_32_code normalization), so kept the old path deleted.
Fallout from main's fabric fixes (validated by the boiler-3 real-cert pin which
still reproduces at delta 0):
- re-pinned the boiler-1 + boiler-instant-hw ASHP snapshot scores;
- main's §14.2 gas-boiler main-fuel derivation resolved the BGB/102 baseline
gap, so `test_gas_boiler_instant_hw_before_baselines` is now a passing test
(was an xfail tripwire).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The Elmhurst §15.1 "Insulated: No Insulation" label was lodged but absent
from `_ELMHURST_CYLINDER_INSULATION_LABEL_TO_SAP10`, so
`_elmhurst_cylinder_insulation_code` raised UnmappedElmhurstLabel — blocking
the parse of every Solar PV example cert (the solar `before` lodges "No
Insulation"). An uninsulated cylinder has no insulation *type*, so per the
no-misleading-insulation convention it maps to `cylinder_insulation_type =
None` rather than naming a material; the lodged 0 mm thickness carries the
storage-loss signal the SAP 10.2 Table 2 dispatch needs.
Slice 1 of the Solar PV Recommendation Generator (ADR-0026).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The API `floor_heat_loss` code is authoritative — confirmed by joining each
single-BP cert's code to its independent `floors[].description` (which the
gov register publishes alongside the code):
code 1 ↔ "To external air" (exposed, 9/9)
code 2 ↔ "To unheated space" (semi-exposed, 6/6)
code 3 ↔ "(other premises below)" (partially htd, 9/9)
code 6 ↔ "(another dwelling below)" (party, 176/176)
code 7 ↔ "Solid"/"Suspended …" (ground, all)
Code 3 was mis-mapped to "To unheated space" (semi-exposed) and, on
mid-/top-floor flats, had its floor area zeroed entirely by the
dwelling-level exposure heuristic. RdSAP 10 §3.12 (PDF p.25) classes a
flat's floor over non-domestic "other premises … heated, but at different
times" as "above a partially heated space" → the §5.14 (PDF p.47) constant
U=0.7 W/m²K — distinct from semi-exposed (Table 20) and party (no loss).
Fix: the mapper sets `is_above_partially_heated_space` on the floor=0
dimension for code 3 (string → "(other premises below)" for fidelity), and
the heat-transmission step lets that per-BP lodgement override the flat
suppression upward (mirroring the existing exposed / "another dwelling
below" overrides). The cascade already routes is_above_partial → U=0.7.
Re-pins golden cert 7536-3827: its Ext2 (bp3) lodges code 3, but the cert's
lossy `floors[]` summary dropped that description, so a prior agent guessed
"code 3 = ground" (U=1.12) and concluded the residual was an irreducible
"register-rounding" artifact. It was this bug: Ext2 floor U 1.12 → 0.70,
PE -6.1952 → -5.6414, CO2 -0.1639 → -0.1492 (both toward 0), SAP unchanged.
Eval: 909 computed, 45.1% → 45.3% within 0.5, mean|err| 1.702 → 1.659,
<1.0 59.5% → 60.2%. 13 code-3 certs improve (0380 +3.71 → -0.63, 0350
+7.82 → +0.83, 2610 +7.47 → -1.29); the few that overshoot were already
failing and carry independent fabric bugs (9763's walls = 8 W/K for 60 m²).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
API floor_heat_loss=8 is observed on EXTENSION building parts whose
floor sits over a heated space within the SAME dwelling (an upper-storey
extension over a heated room). RdSAP 10 §3 gives an internal floor
between heated storeys no floor heat loss — mechanically identical to a
code-6 party floor. `_api_floor_type_str` had no entry for 8, raising
UnmappedApiCode and blocking certs 0370-2254-6520-2426-5971 and
0997-1206-9806-0715-2904.
Map code 8 to the code-6 no-heat-loss string "(another dwelling below)"
(consumed by heat_transmission's party-floor suppression; != "Ground
floor" so the §5 (12) suspended-timber rule stays inert). Empirically
confirmed against both certs: the no-heat-loss treatment lands them
within 0.5 of lodged (0370-2254 68.92 vs 69; 0997-1206 40.68 vs 41),
whereas Ground-floor / unheated / external mappings miss 0997 by ~4 SAP.
Eval computed 906→908. Regression green (only the pre-existing
test_total_floor_area fails); pyright net-zero (38=38).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A floor lodged API floor_heat_loss=6 ("another dwelling below") sits over
another heated dwelling, so it is a party floor with no heat loss (RdSAP
10 §3). The mapper mapped code 6 → None and the heat-transmission step
drove floor exposure solely from the dwelling-level `has_exposed_floor`
flag — which is keyed only on the dwelling_type label and defaults a
"Ground-floor flat" to an exposed floor. So a ground-floor flat above a
basement dwelling kept its full ground-floor heat-loss area.
Map code 6 → "(another dwelling below)" (still != "Ground floor", so the
§5 (12) suspended-timber rule stays inert) and have the cascade suppress
that BP's floor when its floor_type carries the signal, mirroring the
roof's existing "another dwelling above" per-BP party override.
Cert 2115-4121-4711-9361-3686 (ground-floor flat, floor_heat_loss=6):
floor_w_per_k 47.85 → 0; SAP -23.44 → -4.41. Cert 0350-…-6435 -12.38 →
-0.55; 0926-…-9024 -2.35 → -0.82. Eval mean |err| 1.982 → 1.944.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A Summary §14.0 Table 4b gas boiler (SAP code 101-119) lodges no §14.0
"Fuel Type" string in the newer Elmhurst export. The carrier was resolved
only from §15.0 "Water Heating Fuel Type" — fine when the same boiler
heats the water, but a gas boiler paired with a SEPARATE electric
immersion lodges §15.0 "Electricity", so `_elmhurst_gas_boiler_main_fuel`
returned None and the cascade strict-raised MissingMainFuelType.
Cert 001431 boiler-1/boiler-2 "before" variants are exactly this config:
§14.0 SAP code 102/104 (mains-gas boiler), §15.0 electric immersion
(code 909), §14.2 Meters "Main gas: Yes". The meter flag is the
authoritative carrier signal — a 101-119 boiler on mains gas burns mains
gas — so adopt it (SAP10 main_fuel 26 per _ELMHURST_MAIN_FUEL_TO_SAP10
"Mains gas") when §15.0 can't disambiguate. §15.0 gas/LPG still wins when
present (keeps LPG-vs-mains-gas precision); no mains-gas meter + non-gas
§15.0 still strict-raises rather than guessing.
Spec: SAP 10.2 Table 4b "Seasonal efficiency for gas and liquid fuel
boilers" (PDF p.168), rows 101-119. Both certs now resolve main_fuel=26
and compute (was: hard raise).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A "Pitched, sloping ceiling" (roof_construction == 8) lodges its
insulation in the dedicated `sloping_ceiling_insulation_thickness` field,
not `roof_insulation_thickness` (which stays None — the loft-joist field
is meaningless for a slope-following ceiling). The schema dataclasses
dropped that field, so `from_dict` discarded it and the cascade treated
the slope as uninsulated; worse, the pre-1950 None-fallback forced 0 mm
(U=2.30), over-stating roof heat loss ~74%.
Surface the field on SapBuildingPart (schemas 21.0.0 / 21.0.1) and prefer
it in `_api_resolve_sloping_ceiling_thickness` when it carries a NUMERIC
thickness: "100mm" now reaches Table 17 column (1a) "Insulated slope –
sloping ceiling, mineral wool/EPS" (RdSAP 10 §5.11.3 p.44 — 100 mm →
U=0.40) instead of 2.30. Categorical lodgements ("AB" As Built / "NI")
are not measured thicknesses, so they fall through to the existing
as-built rule (Table 18 col (3) via is_pitched_sloping_ceiling).
Cert 9884-3059-9202-7506 (code 8, age B, sloping 100 mm): SAP −5.54 → +0.06.
Cert 8036-2925-6600-0202: −4.94 → +1.55. No regressions in the roof-8
cohort (the "AB" certs are unchanged). Eval headline 43.8% → 44.3% within
0.5; golden fixtures incl. 6035 green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The 2026 API sample raised UnmappedApiCode on `gable_wall_type` 2 (10 certs)
and 3 (4 certs) — the two RR gable variants beyond Party(0)/Exposed(1).
Sim case 21 (an Elmhurst replica of API cert 2818-3053-3203-2655-9204:
gable_wall_type_1=2, gable_wall_type_2=3) lodges them as "Sheltered" and
"Connected", confirming **2=Sheltered, 3=Connected**.
- Mapper: `_API_TYPE_1_GABLE_TYPE_TO_KIND` gains 2 → `gable_wall_sheltered`,
3 → `connected_wall` (U=0, area deducts — already handled).
- Calculator: new `gable_wall_sheltered` branch. The API path lodges no
per-gable U, so the cascade DERIVES it as RdSAP 10 Table 4 (p.22)
Sheltered = 1/(1/U_wall + 0.5) — back-solved + validated against case 21
(U_wall 1.10 → 0.71) and case 20 (1.70 → 0.92). A lodged U (Summary path)
still rides through as an override.
API sample: 14 raises clear → `computed` 882 → 896, `raise:ValueError` 16 → 2.
Summary path unchanged (Sheltered stays `gable_wall_external` + lodged U, so
cert 000487's hand-built fixture is untouched). 2861 pass (lone
test_total_floor_area pre-existing); pyright strict net-zero (32=32 / 12=12).
NOTE: the derived Sheltered U on cert 2818 lands at 0.92 not 0.71 because the
cascade computes its 440 mm solid-brick wall U as 1.70 (the 220 mm default) —
a SEPARATE wall-U-vs-thickness bug (next slice, validated by case 21's 1.10).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A Detailed room-in-roof lodges "Stud Wall" surfaces, but the cascade billed
every one through Table 17 from its insulation — over-counting fabric on
internal studs that carry no heat loss. sim case 20's two studs lodge §8.1
Default U-value 0.00 and the P960 worksheet omits them from BOTH fabric heat
loss (§3: (33)=285.9847) and total exposed area (31)=239.68; the cascade
computed ~0.52 each → (33) +4.16 W/K and continuous SAP 43.05 vs 43.6322.
Gate the drop on the lodged Default U-value: 0.00 → internal knee wall,
return None (no heat loss, no area); positive → a real exposed knee wall
(cert 000565 Ext2 Detailed: 0.31 / 0.10) that still falls through to the
Table-17 path. The earlier over-broad "drop all studs" zeroed 000565's
genuine studs — this keeps them.
Pins test_summary_001431_case20_fabric_heat_loss_matches_worksheet_line_33
((33)=285.9847 at 1e-4); case 20 continuous SAP now EXACT (43.6322). 2850
pass (the lone test_total_floor_area failure is pre-existing on base);
pyright strict net-zero (32=32).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice f68cea27 (re-homed here as 97f44b53) added a guard to
_is_elmhurst_roof_window — "a window lodged on a wall is vertical by
definition" — to keep 001431's two "Double pre 2002" External-wall units in
the vertical sap_windows list for the Modelling draught-proofing count. But
that guard fires on the §11 `location` string, which is an unreliable
lodging artifact: every one of cert 000516's six §11 rows reads "External
wall", and only the U-value separates the five vertical panes (U 2.8) from
the one genuine rooflight (U 3.1, area 1.18, lifted to 3.40 by the Table 24
lookup). Elmhurst's own worksheet routes that U 3.1 "External wall" unit
through (27a) Roof Windows — so location is NOT a vertical signal and the
U > 3.0 backstop (RdSAP 10 §3.7.1) is what matches the worksheet.
Removing the guard restores both 000516 pins
(test_summary_000516_full_chain_sap_matches_worksheet_pdf_exactly,
test_from_elmhurst_site_notes_matches_hand_built_000516) with no other
regression (2879 pass; the lone test_total_floor_area failure is
pre-existing on the branch base, unrelated to window classification).
The extractor half of 97f44b53 (capturing the standalone "BFRC data" §11
row) is retained — it is independent of this classifier and harmless here.
The 001431 Modelling draught-proofing count must instead include roof
windows (the draught_proofed-on-SapRoofWindow approach noted in the glazing
handover), which is feature/bill-derivation's front, not this branch.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cert 001431's §11 lodges 17 windows but only 14 surfaced, via two distinct gaps:
1. Extractor (_extract_windows_from_layout): the one "Double glazing, known
data" row whose §11 Data-Source cell is "BFRC data" was rejected — it is
laid out as a standalone keyword line with the U-value on the next line
and lodges no Frame Type/Factor/Gap cells, so it never matched the joined
"<source> <U>" Manufacturer-line shape. Now anchored by a standalone
data-source form, with the RdSAP 10 §3.7 default frame factor (0.7) for
the absent frame cell.
2. Mapper (_is_elmhurst_roof_window): the two "Double pre 2002" rows
(U 3.1 / 3.4 > 3.0) were reclassified as roof windows by the U-value
backstop even though both are lodged on an "External wall". A window
lodged on a wall is vertical by definition; guard the U-value backstop so
it only fires when location/BP give no roof signal.
With both closed: 17 sap_windows, 0 misrouted to sap_roof_windows.
Re-homed onto the mapper-validation line from feature/bill-derivation
(orig f68cea27); the modelling-only regression test
(tests/domain/modelling/test_window_extraction_001431.py) stays on
bill-derivation. KNOWN: the mapper guard breaks cert 000516's
test_summary_pdf_mapper_chain pins (W6 U=3.10 routing) — must be resolved
before this PRs to main.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The Modelling glazing overlay's draught-proofing recompute (RdSAP 10 §8.1 —
a count over openable windows + doors) needs every openable window captured
with its draught_proofed flag. cert 001431's §11 lodges 17 windows but only
14 surfaced, via two distinct gaps:
1. Extractor (_extract_windows_from_layout): the one "Double glazing, known
data" row whose §11 Data-Source cell is "BFRC data" was rejected — it is
laid out as a standalone keyword line with the U-value on the next line
and lodges no Frame Type/Factor/Gap cells, so it never matched the joined
"<source> <U>" Manufacturer-line shape. Now anchored by a standalone
data-source form, with the RdSAP 10 §3.7 default frame factor (0.7) for
the absent frame cell.
2. Mapper (_is_elmhurst_roof_window): the two "Double pre 2002" rows
(U 3.1 / 3.4 > 3.0) were reclassified as roof windows by the U-value
backstop even though both are lodged on an "External wall". A window
lodged on a wall is vertical by definition; guard the U-value backstop so
it only fires when location/BP give no roof signal. The backstop's only
pinned cert (000516 W6) hand-builds its sap_roof_windows and so is
unaffected.
With both closed: 17 sap_windows, 0 misrouted to sap_roof_windows, 14
draught-proofed — reconstructing Elmhurst's lodged 84% (16/19 = (14 windows
+ 2 doors) / (17 windows + 2 doors)). Full calculator + modelling +
orchestration suites green (1885 pass); the 2 glazing draught-proofing
xfails remain (the overlay recompute is the glazing agent's front).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`test_epc_property_data_round_trips[RdSAP-Schema-21.0.1]` failed with
`sap_roof_windows: None != []` — a normalization mismatch, not lost data.
The 21.0.1 fixture has no roof windows, but the 21.0.1 API mapper emitted
an empty list `[]` while the domain field defaults to None
(`Optional[List[SapRoofWindow]] = None`), the 21.0.0 path yields None, and
the persistence reload yields None (roof windows aren't stored yet — doc
§2.4). Append `or None` so "no roof windows" has one canonical
representation across mapper paths and the round-trip.
No data-loss change: a cert WITH roof windows still produces the
populated list (test_golden_fixtures pins a 6-roof-window cert), and the
§2.4 roof-window persistence gap remains separately tracked. Full
sap10_calculator + documents_parser + epc-repository suites pass (2420);
pyright unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
PR feedback (dancafc): the `_api_resolve_wall_insulation_thickness` tests
passed literals straight into the Act call. Bind them as named variables
in Arrange (`lodged_thickness`, `measured_value_mm`, `ni_lodgement`) and
have the asserts reference those names, so the Act line reads
declaratively and the inputs/expectations are stated once. Applied to all
three tests in the class. No behaviour change; tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Completes the secondary-glazing family. S0380.235 mapped the unknown-data
(7) and normal-emissivity (11) secondary variants; the RdSAP-21.0.1
`glazed_type` enum also defines code 12 "secondary glazing, low
emissivity", whose Elmhurst §11 label "Secondary glazing - Low
emissivity" was unmapped and would strict-raise. Cascade code 12 carries
the same daylight/solar bucket as 7/11 (g_L=0.80, g⊥=0.76); the lodged
manufacturer U/g drive §3/§6. With this the double family (codes 1/2/3/
7/13 via their Elmhurst phrasings) and the secondary family (4/11/12) are
fully covered. Coverage test extended.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The double_glazing recommendation fixture (Summary_001431) exercises every
RdSAP-21 §11 glazing lodging in one cert; five labels were missing from
`_ELMHURST_GLAZING_LABEL_TO_SAP10` and strict-raised `UnmappedElmhurstLabel`:
"Secondary glazing" -> 7 (Table 6b "secondary glazing", g_L 0.80)
"Secondary glazing - Normal emissivity" -> 11 (RdSAP-21 secondary normal-E, g_L 0.80)
"Triple pre 2002" -> 10 (triple pre-2002, g_L 0.70)
"Triple with unknown install date" -> 6 (generic triple glazed, g_L 0.70)
"Single glazing, known data" -> 15 (single known-data, g_L 0.90)
The glazing code's only cascade effect is the §5 (66)..(67) daylight factor
g_L in `_G_LIGHT_BY_GLAZING_CODE` (single 0.90 / double+secondary 0.80 /
triple 0.70); the lodged manufacturer U-value and solar_transmittance drive
§3 / §6 directly (`_g_perpendicular` prefers the lodged value). Codes are the
semantically-exact RdSAP-21 rows within the correct g_L bucket, kept distinct
for the strict-raise audit trail. Adds a full-coverage test over all 13
distinct labels. Suite 2413 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Appendix G4 (PDF p.72-73). A PV diverter routes surplus PV
generation (the would-be export EPV,m × (1 − βm)) to an immersion heater
in the hot-water cylinder. Per G4 step 4:
SPV,diverter,m = EPV,m × (1 − βm) × 0.8 × fPV,diverter,storageloss
(0.8 = cylinder heat-acceptance; fPV,diverter,storageloss = 0.9 for the
higher storage temperature), clamped to ≤ (62)m + (63a)m, and entered as
the negative worksheet (63b)m (step 5). The β factor is computed on the
PRE-diverter (219) per the §3a note (lines 5485-5486). Effects:
- (64)m = (62)m + (63b)m → less main-system water-heating fuel (219);
- export drops to EPV,ex,m = EPV,m(1 − βm) + (63b)m / 0.9 (§4 p.94
line 5501); the onsite dwelling portion EPV,m × βm is unchanged.
Inclusion (G4 step 1) requires ALL of: a PV system connected to the
dwelling; a cylinder larger than (43) average daily HW use; no solar
water heating; no battery — else the diverter is disregarded.
Three layers:
- extractor reads Summary §19 "Diverter present"; schema 21.0.0/21.0.1
SapEnergySource gains `pv_diverter` (API `sap_energy_source.pv_diverter`);
- `Renewables.pv_diverter_present` + domain `SapEnergySource.pv_diverter_present`,
set in both the Elmhurst and API mapper paths;
- `_pv_diverter_monthly_kwh` applies the G4 math after the β split;
`cert_to_inputs` recomputes (219) and the PV export.
On simulated case 19 (electric storage heaters, 7-hour, PV + diverter):
SAP continuous 50.33 → 51.34 (worksheet 51.2221; both round to the
lodged 51), cost (255) 1847.5 → 1812.3 (ws 1816.6), CO2 (272) 3331 →
3120 (ws 3126), with (233a) dwelling 1280.6 (ws 1280.4). The residual
+0.11 SAP is an upstream winter Appendix-M monthly-EPV-shape gap +
fabric (33) +1.0, tracked as the next case-19 cause. Suite: 2412 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The gov-EPC API mapper sets BOTH roof_construction (int) and
roof_construction_type (str, derived via _API_ROOF_CONSTRUCTION_TO_STR),
but the Elmhurst mapper set only the string — leaving roof_construction
None on every site-notes cert. The SAP cascade reads the STRING (so SAP
cross-mapper parity always held), but consumers of the int (e.g.
domain/sap10_ml/transform.py ML aggregates `main_dwelling_roof_
construction`) silently saw None on the Elmhurst path.
New `_elmhurst_roof_construction_int` maps the Elmhurst roof-type code to
the same SAP10 int the API lodges (F→1, PN→3, PA→4, PS→8, S/A→7),
harvested from the committed Summary fixtures. Unlike the wall map it
returns None (not a strict-raise) for unmapped codes: the int is not
cascade-load-bearing, so an unknown roof must not block the cert (vaulted
5 / thatched 6 / NR omitted until a fixture surfaces them).
The 6 hand-built U985 reference fixtures gain the matching
roof_construction int (4/4/3 etc.) so test_from_elmhurst_site_notes_
matches_hand_built_* still asserts structural parity. SAP output is
unchanged (cascade reads the string). §4 suite green (2407 passed); the
two pre-existing stone-§5.6 sap10_ml failures are unrelated/out of scope.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP10 `wall_construction == 6` is canonically WALL_SYSTEM_BUILT — a
WALL TYPE — but the gov-EPC basement heuristic hijacked it: Elmhurst
lodges both "SY System build" and "B Basement wall" as code 6, and the
API lodges basements as code 6 too, so a system-built wall was
mis-flagged `main_wall_is_basement` → wrong RdSAP §5.17 / Table 23
u_basement_wall/u_basement_floor overrides, and downstream the solid-wall
Recommendation Generator couldn't offer EWI/IWI on system-built walls.
System-built stays the wall type on its canonical code 6; the basement
signal moves OFF code 6 to a dedicated `is_basement` (SapAlternativeWall)
/ `wall_is_basement` (SapBuildingPart) Optional[bool] flag:
- Elmhurst: `_elmhurst_wall_is_basement` sets it from the distinct
"SY"/"B" labels (False for SY, True for B, None otherwise).
- gov-EPC API: per-wall code 6 can't be told apart at lodging time, so
`from_api_response` post-processes via `_clear_basement_flag_when_
system_built` — when the cert addendum marks the dwelling system-built,
the code-6 basement heuristic is cleared. A genuine basement (no
addendum signal) keeps the code-6 fallback.
- `main_wall_is_basement` / `is_basement_wall` honour the flag when set,
else fall back to the code-6 heuristic — so untouched API basements and
the cert 000565 "B" cohort are unchanged.
`EpcPropertyData.system_build` is a derived property over the wall type:
the MAIN wall is system-built iff `wall_construction == 6` and it is not
flagged basement. System-built lives on `wall_construction`; the basement
attribute is separate.
Acceptance: a system-built main wall (Elmhurst SY, or API addendum
system_build) → wall_construction == 6, main_wall_is_basement is False,
system_build is True; a genuine basement main wall → main_wall_is_basement
is True, system_build is False. Full §4 suite green (2404 passed).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP10 `wall_construction == 6` is canonically WALL_SYSTEM_BUILT, but
the gov-EPC basement heuristic hijacked it: Elmhurst lodges both "SY
System build" and "B Basement wall" as code 6, so a system-built wall
was mis-flagged `main_wall_is_basement` and routed to the RdSAP §5.17
`u_basement_wall` override instead of the system-built U-value table.
System-built stays on its canonical code 6; the basement signal moves
to an explicit `is_basement` (SapAlternativeWall) / `wall_is_basement`
(SapBuildingPart) Optional[bool] flag, set by the Elmhurst mapper from
the distinct "SY"/"B" codes via `_elmhurst_wall_is_basement` (True for
B, False for SY, None otherwise). The `main_wall_is_basement` /
`is_basement_wall` properties honour the flag when set and fall back to
the gov-EPC API code-6 heuristic when None — so the API path (basement
lodged as integer 6, no flag) and the cert 000565 "B" cohort are
unchanged.
Acceptance (a recommendation-summary generator depends on it): a
system-built MAIN wall reports wall_construction == 6 AND
main_wall_is_basement is False; a genuine basement main wall still
reports main_wall_is_basement is True.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
